钙激活性中电导钾离子通道在子宫内膜癌组织中的表达及其在细胞增殖中的作用

Intermediate-conductance-Ca^(2+)-activated K^+ channels are overexpressed in endometrial cancer and involved in regulating proliferation of endometrial cancer cells

目的探讨子宫内膜癌组织中钙激活性中电导钾离子通道(IKCal)的表达变化及其在子宫内膜癌细胞增殖中的作用。方法应用蛋白印迹(western blot)法、RT-PCR 技术来研究13份正常子宫内膜及25份子宫内膜癌组织中 IKCal mRNA 和蛋白的表达;利用 IKCal 的阻断剂——克霉唑(clotrimazole),使用小分子干扰 RNA(siRNA)的 RNA 干扰技术和氚胸腺嘧啶核苷掺入试验等观察子宫内膜癌 HEC-1A 细胞增殖的变化。结果子宫内膜癌组织中 IKCal mRNA 的阳性表达率及表达水平(分别为84%、0.89±0.52)明显高于正常子宫内膜组织(分别为8%、0.14±0.12,P 均<0.01)。子宫内膜癌组织中 IKCal 蛋白的阳性表达率及表达水平(分别为80%、1.18±0.41)也明显高于正常子宫内膜组织(分别为15%、0.71±0.26,P 均<0.01)。子宫内膜癌组织中 IKCal mRNA 和蛋白的表达水平与手术病理分期无关(P>0.05),但与病理分级有关(P<0.05)。克霉唑呈剂量和时间依赖性方式阻滞 HEC-1A 细胞的增殖。与转染阴性对照 siRNA 的细胞比较,转染 IKCal siRNA 的 HEC-1A细胞 IKCal 蛋白的表达水平降低,为转染阴性对照 siRNA 的细胞的(48.27±9.07)%。与转染阴性对照 siRNA 的 HEC-1A 细胞比较,转染 IKCal siRNA 能减少细胞的增殖(P<0.05)。结论 IKCal 的异常表达与子宫内膜癌的发展密切相关,降低其表达可减少子宫内膜癌细胞的增殖。

Objective To study the expression of intermediate-conductance-Ca^2＋-activated K^＋ （ IKCal ） channels in endometrial cancer and its role in regtdating proliferation of endometrial cancer cells. Methods Western blot and RT-PCR were used to examine the expression of IKCal channels in 13 normal endometrial specimens and 25 endometrial cancer specimens; and RNA interference （RNAi）, [3H] thymidine incorporation, and inhibitor of IKCal channel were used to explore the role of IKCal channels in regulation of proliferation of endometrial cancer cells HEC-IA. Results The expression rate and level of IKCal mRNA in endometrial carcinoma （84% , 0. 89 ±0. 52） were higher than in normal endometria （8%, 0. 14 ± 0. 12; P 〈 0. 01 ）. The expression rate and level of IKCal protein in endometrlal carcinomas （ 80%, 1.18 ±0. 41 ） were higher than in normal endometria （ 15% , 0. 71 ±0. 26; P 〈 0. 01 ）. CIotrimazole, an inhibitor of IKCal channels known to suppress the function of the channels, caused a beth time- and dosedependent decrease in cell number of HEC-1A cell. Western blot analysis revealed that the IKCal level in whole lysates of the cells transfected with target-IKCal small interference RNA （siRNA） was （48.27 ＋ 9. 07 ） % of that found in the cells transfected with non-silencing RNA ; [ 3 H ] thymidine incorporation in HEC-1A cells transfected with target-IKCal siRNA was also reduced, siRNA inhibited HEC-1A cell proliferation, compared with the cells transfected with non-silencing RNA （ P 〈 0. 05 ）. Conclusion The expression of IKCal channels may be closely rehited to the proliferation of endometrial cancer, and down regulation of its expression may suppress its development.